Memory control groups are currently bolted onto the side oftraditional memory management in places where better integration wouldbe preferrable. To reclaim memory, for example, memory control groupsmaintain their own LRU list and reclaim strategy aside from the globalper-zone LRU list reclaim. But an extra list head for each existingpage frame is expensive and maintaining it requires additional code.

This patchset disables the global per-zone LRU lists on memory cgroupconfigurations and converts all its users to operate on the per-memorycgroup lists instead. As LRU pages are then exclusively on one list,this saves two list pointers for each page frame in the system: